Study on Damage Evolution Mechanism of Concrete under Uniaxial Tension

2012 ◽  
Vol 238 ◽  
pp. 46-50
Author(s):  
Wei Feng Bai ◽  
Ying Cui ◽  
Qian Wang ◽  
Jun Feng Guan ◽  
Jian Wei Zhang
Keyword(s):  
Uniaxial Tension ◽  
Damage Mechanics ◽  
Failure Process ◽  
Damage Model ◽  
Damage Mechanism ◽  
Deformation Characteristics ◽  
Deformation And Failure ◽  
Damage And Failure ◽  
Basic Parameters ◽  
Fundamental Research

The damage and failure mechanism of quasi-brittle materials is the most fundamental research topic in Damage Mechanics. In this paper, the mesoscopic damage mechanism of concrete under uniaxial tension was discussed. The rupture and yield damage modes in meso-scale were introduced as the two basic parameters to define the damage accumulated variable. The results show that the proposed statistical damage model can accurately predict the whole deformation and failure process of concrete under uniaxial tension, including the two-stage deformation characteristics and the size effect.

Numerical Simulation of Gun Bore Damage during Engraving Process of Driving Band

2017 ◽  
Vol 1142 ◽  
pp. 363-366
Author(s):  
He Yang Sun ◽  
Chang Zhi Jia ◽  
Yao Xin He ◽  
Tian Xiao Cui
Keyword(s):  
Damage Mechanics ◽  
Failure Process ◽  
Damage Model ◽  
Firing Process ◽  
Computation Method ◽  
Damage Behavior ◽  
Damage And Failure ◽  
Gun Barrel ◽  
Safety Design ◽  
Microscopic Damage

A Damage mechanics finite element numerical computation method was established based on HLC microscopic damage model to solve the problem of damage, crack initialization and growth inside bore during the firing process. The damage and failure process of the bore surface was simulated numerically during multiple rounds of firing. The law of the barrel material performance changing with the number of firing rounds was analyzed during the engraving process of the driving band and compared with the experimental results. It is proved that HLC microscopic damage model can show the complicate damage behavior and predict the cracking defect, which provides a reference for safety design of the gun barrel.

Fatigue-Cumulative Damage Model of RC Crane Girders Strengthened with FRP Strips

2008 ◽  
Vol 385-387 ◽  
pp. 165-168
Author(s):  
Shan Suo Zheng ◽  
Bin Wang ◽  
Lei Li ◽  
Liang Zhang ◽  
Pi Ji Hou
Keyword(s):  
Damage Mechanics ◽  
Flexural Rigidity ◽  
Failure Process ◽  
Damage Model ◽  
Cumulative Damage ◽  
Good Time ◽  
Failure Patterns ◽  
Damage And Fracture ◽  
Cumulative Damage Model ◽  
Frp Strips

The cumulative damage of the reinforced concrete (RC) crane girders occurred by overload, fatigue and other reasons in service may deteriorate the safety of RC crane girders seriously, so it is necessary to analyze the damage mechanism and rationally reinforce them in good time. In this paper, RC crane girder strengthened with CFRP strips is taken as a target, and the mechanical performance degradation under fatigue load is studied. According to the basic theory of continuum damage mechanics, a damage variable is defined by flexural rigidity, and fatigue- cumulative damage model, which describes the process of damage and fracture, is established. The variation law of cumulative damage of RC crane girders strengthened with FRP strips under crane load is discussed, and the failure patterns such as concrete cracking, debonding between CFRP strips and concrete, yield of steel bars etc., are studied. The criterion which can be used to estimate the cumulative damage degree of strengthened RC crane girders is proposed. Finally, the evolution of the fatigue damage in the RC crane girders strengthened with CFRP strips is numerically simulated, and the results show that the proposed model can correctly describe the damage and failure process of strengthened RC crane girders. The research will provide a reference for the damage analysis and reinforcement of RC crane girders strengthened with CFRP strips.

scholarly journals Investigation into the gas adsorption-loading coupling damage constitutive model of coal rock

2021 ◽  
Author(s):  
Zhongzhong Liu ◽  
Hanpeng Wang ◽  
Su Wang ◽  
Yang Xue ◽  
Chong Zhang
Keyword(s):  
Gas Adsorption ◽  
Coupling Effect ◽  
Influencing Factor ◽  
Failure Process ◽  
Damage Model ◽  
Strain Curve ◽  
In Situ Stress ◽  
Compression Tests ◽  
Damage And Failure ◽  
Coal Rock

Abstract Coal and gas outburst is the result of comprehensive action of in-situ stress, gas and mechanical properties of coal rock. The coupling effect of loading and gas adsorption eventually leads to the coal rock failure. Based on the principle of strain equivalence and considering the coupling effect of gas adsorption and stress loading, an adsorption-loading coupling damage model is established which breaks through the bottleneck of only considering single influencing factor. Taking briquette samples with controllable properties as the research object, uniaxial compression tests of coal rock at different gas adsorption pressures are carried out, and the model is verified based on the test results. The results of model calculation and tests show that the meso damage stage of coal body can well correspond to the macroscopic deterioration phenomenon and it is in good agreement with the stress-strain curve. It is proved that the model has good applicability and can accurately describe the damage and failure process of coal rock.

scholarly journals Investigation on tensile deformation and failure for 5052 aluminum alloy based on continuum damage model

2021 ◽  
Vol 2085 (1) ◽  
pp. 012039
Author(s):  
Pengjing Zhao ◽  
Jingpin Jiao ◽  
Gang Fang ◽  
Zhanghua Chen ◽  
Xiang Gao
Keyword(s):  
Finite Element ◽  
Aluminum Alloy ◽  
Damage Mechanics ◽  
Tensile Deformation ◽  
Damage Model ◽  
Inversion Method ◽  
Failure Behavior ◽  
Distribution Law ◽  
Deformation And Failure ◽  
Simulation Results

Abstract A VUMAT user material subroutine for the Lemaitre continuous damage mechanics model was developed based on the finite element solver ABAQUS/Explicit platform to investigate the deformation and failure behavior of 5052 aluminum alloy. The mechanical property parameters and damage parameters of 5052 aluminum alloy were identified by the inversion method combining tensile test and finite element simulation. The numerical simulation results showed that the force-displacement curves predicted by the established damage model were in good agreement with the experimental measurement, and the fracture location was close to the experimental results, which verified the accuracy and effectiveness of the damage parameters. The growth and distribution law of damage variable could be intuitively represented by the simulation results by the Lemaitre damage model.

Stochastic Damage Constitutive Model for Concrete Subjected to Uniaxial Tension Stress

2009 ◽  
Vol 417-418 ◽  
pp. 921-924
Author(s):  
Ming Xie ◽  
Shan Suo Zheng ◽  
Bin Wang ◽  
Lei Li ◽  
Wei Wang
Keyword(s):  
Constitutive Model ◽  
Uniaxial Tension ◽  
Experimental Situation ◽  
Failure Process ◽  
Damage Model ◽  
Tension Stress ◽  
Calculation Results ◽  
Concrete Damage ◽  
Damage Constitutive Model ◽  
Stochastic Damage

A stochastic damage constitutive model is proposed based on Kelvin spring-damper model and Li Jie spring stochastic damage model. The model is made up by microscopic spring-slipper element. The slipper, parallel connected with spring, is introduced to consider the plasticity effect of concrete. Damage failure process of concrete subjected uniaxial tension is divided into spring broken state and slipper broken state to describe the elastic stage and plastic stage of damage respectively. In the light of energy conservation during the process of damage failure, stochastic damage constitutive equation of concrete material subjected to uniaxial tension stress is derived. Comparisons between test results and theoretical calculation results verify that the established constitutive damage equations are accord with the experimental situation, and the experimental data are observed undulated with theoretical curve in the range of variance. The research results can apply in the actual engineering.

Fire Response Calculation Based on Damage Mechanics

2013 ◽  
Vol 639-640 ◽  
pp. 1193-1199 ◽  
Author(s):  
Song Hua Tang ◽  
Ying She Luo ◽  
Shui Ping Yin ◽  
Yong Hong Li ◽  
Chao Chen ◽  
...  
Keyword(s):  
Temperature Field ◽  
Heat Conduction ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Concrete Slab ◽  
Failure Process ◽  
Strength Theory ◽  
Fire Response ◽  
Damage Evolution Equation ◽  
Damage And Failure

Damage mechanics is introduced into the fire response calculation of the concrete structure. The damage mechanics equations for fire response calculation are established. They are the damage evolution equation based on “residual strength” theory, heat conduction equations, and elastic mechanical equations. The fire response calculation of a concrete slab under external load and fire is shown. ANSYS is selected for calculating. The temperature field and stress field are obtained, the damage and failure process are described using the technique of killing or activating elements in ANSYS, and the fire resistance of the slab is obtained.

A Coupled Elastic-Plastic Damage Model for Rock Material

2014 ◽  
Vol 488-489 ◽  
pp. 799-802
Author(s):  
Hong Jie Chen ◽  
Wei Ya Xu ◽  
Ru Bin Wang ◽  
Wei Wang
Keyword(s):  
Damage Mechanics ◽  
Damage Model ◽  
Confining Pressure ◽  
Damage Mechanism ◽  
Coupling Model ◽  
Internal Variable ◽  
Elastic Plastic ◽  
Softening Behavior ◽  
Plastic Damage ◽  
Damage Constitutive Model

With complex mechanics character and under the action of compression and tension in tri-direction, rock will show coupled plastic-damage mechanism as its basic character. Phenomenological coupled elastic-plastic-damage constitutive model with internal variable is proposed based on thermal mechanics theory, elastic law and macro damage mechanics. Numerical experiments on this model and analyze the model character. The result shows that the coupling model could realize rocks softening behavior brought about by damage and strength enlargement caused by confining pressure increasing.

scholarly journals A Modified Fatigue Damage Model for High-Cycle Fatigue Life Prediction

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Meng Wang ◽  
Qingguo Fei ◽  
Peiwei Zhang
Keyword(s):  
Damage Mechanics ◽  
High Cycle Fatigue ◽  
Failure Process ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Cycle Fatigue ◽  
Damage State ◽  
Damage Evolution Equation ◽  
Metal Material ◽  
Python Language

Based on the assumption of quasibrittle failure under high-cycle fatigue for the metal material, the damage constitutive equation and the modified damage evolution equation are obtained with continuum damage mechanics. Then, finite element method (FEM) is used to describe the failure process of metal material. The increment of specimen’s life and damage state can be researched using damage mechanics-FEM. Finally, the lifetime of the specimen is got at the given stress level. The damage mechanics-FEM is inserted into ABAQUS with subroutine USDFLD and the Python language is used to simulate the fatigue process of titanium alloy specimens. The simulation results have a good agreement with the testing results under constant amplitude loading, which proves the accuracy of the method.

scholarly journals Deformation and damage dynamic characteristics of coal–rock materials in deep coal mines

2017 ◽  
Vol 28 (1) ◽  
pp. 58-78 ◽  
Author(s):  
Jiankun Xu ◽  
Rui Zhou ◽  
Dazhao Song ◽  
Nan Li ◽  
Kai Zhang ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Axial Strain ◽  
Failure Process ◽  
Surface Damage ◽  
Damage Mechanism ◽  
Critical Values ◽  
Deformation And Failure ◽  
Rock Materials ◽  
Macroscopic Deformation ◽  
Coal Rock

The deformation and damage characteristics of surrounding rock grow gradually with the increase of mining depth, and the mechanical behavior and damage mechanism of coal–rock materials vary greatly. In order to reveal the deformation and damage dynamic characteristics of coal–rock materials in deep mines, the macroscopic deformation characteristics of coal, rock, and concrete samples under uniaxial compression were studied. The macroscopic deformation amount, velocity, and acceleration of different samples were analyzed. The coal and rock samples exhibit regular dynamic characteristics before they lose stability and fail. The axial strain response of the coal samples changes significantly during the compact and elastic deformation stages. Besides, the relationship between the surface damage and the macroscopic deformation of sample was studied by means of visualization and image processing. The macroscopic deformation index of coal–rock materials changes significantly before and after the destabilization and failure. Based on the deformation and failure dynamic characteristics of coal and rock, the evolution rule of deformation critical values was taken as the deformation and destruction stages, which revealed the dynamic characteristics during the deformation and failure process of coal–rock materials in deep mines. The deformation critical values can be used to realize early warning of deformation and fracture of coal and rock materials in deep mines.

Finite Element Simulation of Ductile Failure Process of Spot Welded Joint under Tensile Loading

2014 ◽  
Vol 660 ◽  
pp. 623-627
Author(s):  
Mohamad Shahrul Effendy Kosnan ◽  
Zaini Ahmad ◽  
Abdoulhdi Amhmad Borhana ◽  
Mohd Nasir Tamin
Keyword(s):  
Welded Joint ◽  
Fe Simulation ◽  
Tensile Deformation ◽  
Failure Process ◽  
Damage Model ◽  
Ductile Failure ◽  
Tensile Failure ◽  
Fe Model ◽  
Deformation And Failure ◽  
Spot Welded

Deformation response and failure process of a spot welded joint are investigated in this study. For this purpose, a cross-tension spot welded joint sample made of dual phase steel sheets (DP600) is prepared and tensile tested to failure. Complementary FE simulation of the test is performed. The FE model acknowledges the variation of properties across the spot welded region. Rice-Tracey ductile damage model is approximated and employed in the simulation. Close comparison of load-displacement curves and deformed shape with measured values serve as validation of the FE model. Results show that FE simulation with damage-based model adequately predicts tensile deformation and failure of the spot welded joint. Tensile failure of the joint is confined to the heat affected zone and heat affected/fusion zone interface of the joint. Localized through-thickness necking of the sheet metal is captured. In addition, the predicted fracture of the spot welded joint is accompanied by localized extensive plastic deformation.

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